Project Summary Variants in the genes that encode voltage-gated Ca2+ channels are consistently and robustly associated with schizophrenia, bipolar disorder, and autism spectrum disorder. One of these genes is CACNA2D4, an IDG-elibigle gene that encodes an extracellular Ca2+ channel subunit (?2?-4) expressed in both the brain and retina. In the case of the retina, it has been established that ?2?-4 is required for normal vision. By contrast, the role of this protein in the brain remains understudied; we known neither where in the brain it acts nor what functions it may have there. The long-term goal of this project is to understand how genetic alterations in Cav-channel contributes to the complex etiology of neuropsychiatric disorders. The overall objective of the proposed research is to establish the cellular distribution of ?2?-4 in the mouse brain and which behaviors are disrupted in mice lacking this protein. The specific aims are to (1) define the neural circuits that may be regulated by ?2??4 in the mouse brain and (2) identify cognitive/affective phenotypes in ?2?-4 knock-out mice. To accomplish these aims, we will use antibodies against ?2??4 in immunohistochemical analyses of mouse brain, and behavioral analyses designed to uncover alterations in cognitive or affective function in mice.